I think the fact that these speakers are still sought after by a certain crowd, and to your own comment that they sound 'very good' is a true testament to this 40 year old speaker. If anything, the build quality alone, like so many other Pioneer products of that era is worth the price of admission....But, My SX-1050 and HPM-100's, when playing from "audiophile" acceptable source (I have a Pioneer CD player with a BB DAC) does sound very good...
There are many that say audio nirvana is not achieved until you pay dearly to join the ML electrostatics club. At my age now, I probably can't hear what I used to 30 years ago, but I can listen very critically if I want to. I'm just waiting to listen to my own pair of 100s in a few days, to find out for myself just how they sound. Can they sound as good as my Energy RC series in my HT rig? Maybe yes, maybe no. Speaker technology has change quite a bit in 40 years, but the physics has not.
I don't have any particular brand loyalty, but I do find myself coming back to my Pioneer roots of the 70s - where it all started for me.
redjr...